Induced metabolic alkalosis affects muscle metabolism and repeated-sprint ability

Med Sci Sports Exerc. 2004 May;36(5):807-13. doi: 10.1249/01.mss.0000126392.20025.17.


Purpose: The purpose of this study was to assess the effects of induced metabolic alkalosis, via sodium bicarbonate (NaHCO3) ingestion, on muscle metabolism and power output during repeated short-duration cycle sprints.

Methods: : Ten active females (mean +/- SD: age = 19 +/- 2 yr, VO2max = 41.0 +/- 8.8 mL x kg x min ) ingested either 0.3 g x kg NaHCO3 or 0.207 g x kg of NaCl (CON), in a double-blind, random, counterbalanced order, 90 min before performing a repeated-sprint ability (RSA) test (5 x 6-s all-out cycle sprints every 30 s).

Results: Compared with CON, there was a significant increase in resting blood bicarbonate concentration [HCO3] (23.6 +/- 1.1 vs 30.0 +/- 3.0 mmol x L ) and pH (7.42 +/- 0.02 vs 7.50 +/- 0.04), but no significant difference in resting lactate concentration [La] (0.8 +/- 0.2 vs 0.8 +/- 0.3 mmol x L ) during the NaHCO3 trial. Muscle biopsies revealed no significant difference in resting muscle [La], pH, or buffer capacity (beta(in vitro)) between trials (P > 0.05). Compared with CON, the NaHCO3 trial resulted in a significant increase in total work (15.7 +/- 3.0 vs 16.5 +/- 3.1 kJ) and a significant improvement in work and power output in sprints 3, 4, and 5. Despite no significant difference in posttest muscle pH between conditions, the NaHCO3 trial resulted in significantly greater posttest muscle [La].

Conclusions: As NaHCO3 ingestion does not increase resting muscle pH or beta(in vitro), it is likely that the improved performance is a result of the greater extracellular buffer concentration increasing H efflux from the muscles into the blood. The significant increase in posttest muscle [La] in NaHCO3 suggests that an increased anaerobic energy contribution is one mechanism by which NaHCO3 ingestion improved RSA.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Alkalosis / physiopathology*
  • Analysis of Variance
  • Bicycling / physiology*
  • Exercise Test
  • Female
  • Humans
  • Hydrogen-Ion Concentration
  • Lactates / metabolism
  • Muscle, Skeletal / metabolism*
  • Pulmonary Gas Exchange
  • Sodium Bicarbonate / administration & dosage
  • Sodium Bicarbonate / pharmacology


  • Lactates
  • Sodium Bicarbonate